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Space Shuttle Era: External Tank and Solid Rocket Boosters

It takes an enormous amount of force to lift the space shuttle off the ground and into space. In this video from NASA, learn about the fuel that provides this lift, and the external fuel tank that is specially designed to store all this fuel. Also learn about the solid rocket boosters that work together with the external tank to provide the needed thrust to get the shuttle into orbit.

A space shuttle weighs more than 4 million pounds – about 20 times heavier than a large commercial airplane. Getting it off the ground and accelerating it into space – against the force of gravity – requires an enormous upward force. The shuttle’s external fuel tank and solid rocket boosters provide this lift force by transforming solid and liquid fuel sources into an explosive thrust that lifts the shuttle to an altitude of twenty-four miles in about two minutes, overcoming drag forces and the downward pull of gravity—an example of the fundamental strategy of rocket design based on action/reaction.

The fuel that provides this required lift force is a combination of liquid and solid sources. The liquid fuel is held in the external fuel tank and consists of super-cooled liquid hydrogen and super-cooled liquid oxygen. Mixing and burning the two liquids produces large volumes of very hot gas. The gas expands and presses out the bottom toward the launch pad housing. The resultant opposing upward force provides the needed lift.

The orange insulating foam around the tank keeps the liquids cool until they’re ready to be mixed and heated. The foam also provides an aerodynamic advantage for the whole shuttle stack. In 2003, a piece of insulating foam tore away from the external tank and struck the shuttle’s wing, leading to a hole in the shuttle’s skin and causing the loss of the Columbia and its astronauts. After that accident, NASA engineers re-designed the process used to apply and inspect the insulating foam.

The solid rocket boosters give added quick-acting thrust to get the shuttle into orbit. Inside the boosters are two solid chemicals that, when burned, create an enormous downward force. This force, in keeping with Newton’s Third Law of action and reaction, produces the opposing seven million pounds of upward thrust.

When the space shuttle launched into space, what do you think provided the pressure for lift? How does downward pressure of gas result in lift?

Do you think rocket fuel can be solid? If so, do you think a solid fuel would be more or less efficient than a liquid fuel? Why?

What do you think would happen during a shuttle launch if the floor of the launch pad could be pushed and moved downward as the rockets fired? Would the shuttle be able to lift off?

While Viewing

Before the shuttle, how was rocket fuel stacked for launch? Why did NASA change to the configuration used by the shuttle?

After the first couple of launches, NASA stopped painting the external tank. Why?

What happens to the solid rocket boosters after the shuttle reaches orbit? What happens to the external tank?

After Viewing

How was the external fuel tank involved in the 2003 Columbia accident – and what adjustments did NASA engineers make afterward? How did the adjustments improve both the safety and efficiency of the space shuttle launch?

The video says that the solid rocket boosters produce 7 million pounds of thrust. What does that mean?

Why do you think the solid rocket boosters are designed so that once they’re ignited, they can’t be stopped?

Bonus Question: After the boosters and the external tank drop away, does the shuttle still need its engines?

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